What Is a Tar and Chip Driveway?
What tar and chip (chip seal) is made of, how long pavement engineers say it lasts on roads, and the weather it needs.
Tar and chip is a chip seal: Pavement Interactive describes it as asphalt, typically an emulsion, sprayed on and covered with a single layer of stone, forming a thin wearing surface. A two-layer version is called a double shot. On roads, it says a two to four year service life is common, with five achievable.
What it is made of
Pavement Interactive, a pavement engineering reference, says a bituminous surface treatment, also known as a seal coat or chip seal, is a thin protective wearing surface applied to a pavement or base course. The asphalt is typically an emulsion, and the stone is placed only one layer thick. A treatment built in two layers is often called a double shot.
Why the stone matters
It says the cover stone increases the surface friction of the pavement. Placing too much aggregate causes aggregate pickup, which is why the stone goes down one layer thick.
How long it lasts
Pavement Interactive says a two to four year service life is common for chip seals on roads, and five years is achievable. It says chip seals should go on a pavement that is free of distress or only moderately distressed. Those figures are for roads; a private driveway carries far less traffic.
Weather
Pavement Interactive says a warm day with low humidity is preferred, and that chip seal should never be placed on rainy days or when rain is predicted, because rain can dilute the asphalt binder before it sets.
Compared with hot-mix asphalt
For a hot-mix asphalt driveway, the Colorado Asphalt Pavement Association's residential guideline is a 2-inch bottom course and a 1.5-inch surface course over 6 to 8 inches of crushed aggregate, and it says a well-designed asphalt driveway gives trouble-free service for up to 20 years. South State Paving installs both.
Keep reading
Frequently Asked Questions
Yes. Pavement Interactive uses chip seal, seal coat and bituminous surface treatment for the same thin wearing surface of asphalt covered with stone.
Pavement Interactive says a two to four year service life is common for chip seals on roads, with five years achievable.
Pavement Interactive says a two-layer bituminous surface treatment is often referred to as a double shot.
Sources
The figures on this page come from these sources, read on 2026-09-25. None of them is South State Paving's own claim.
- Pavement Interactive, Bituminous Surface Treatments (chip seals)
- Colorado Asphalt Pavement Association (published by the Asphalt Institute), Best Practices for the Use of Asphalt Driveways, technical brief